The present invention relates to a device for chilling fresh fruit and other fresh food products and, more particularly, to an improved countertop fruit chiller utilizing a Peltier effect thermoelectric device.
Thermoelectric devices operating in accordance with the well known Peltier effect have been used as cooling/heating devices for many years. Such a thermoelectric device comprises an array of semiconductor couples connected electrically in series and thermally in parallel. The semiconductor couples are sandwiched between metalized ceramic substrates. When DC electric current is applied in series to the thermoelectric device, it acts as a heat pump with heat being absorbed on the cold side, thereby cooling it, while heat is dissipated at the other side, where the temperature rises. Reversing the current causes the direction of heat flow to be reversed. The efficiency of the thermoelectric device may be enhanced by attaching a heat sink and a cold sink to the respective hot and cold sides.
Peltier effect devices have long been used to provide coolers and/or heaters for keeping foods fresh or for warming foods for serving. It has also been found and is well known to use forced air convection to aid in heat transfer. A small electric fan is typically used to circulate air past the cold sink and into and through a container for the food, while another fan moves ambient outside air across the heat sink to dissipate heat from it.
Although chillers for fresh fruit and other perishable food products are well known in the art, the market success of such devices has been limited. There appear to be a number of reasons for this lack of market success. One is the cost and heat transfer efficiency of the solid state thermoelectric modules. In addition, such prior art modules have typically been quite fragile, exhibiting low mechanical strength. In addition, the need to provide circulation of cool air to attain the greatest cooling efficiency, has led to complex duct systems which add substantially to the cost of the containers, typically made of molded plastic materials. Long air circulation flow paths also result in heat loss and pressure drop, both of which decrease the efficiency or add to the cost by requiring larger thermoelectric modules.